There are many masks which may be worn for filtering dusty or otherwise impure air for people who wish to purify the air that is passing into their lungs. These generally fit over the nose and mouth and are held in place by a string, an elastic strip or string, or strings or strips which fit around the back of the head or ears, or by adhesive which holds the filter in place in some way. Some of these masks are relatively expensive, and some are rather inexpensive.
The use of a filter to clean or purify the air people breath is not new, and many filter masks have been designed to fit over the nose and mouth. Many of these masks are uncomfortable for various reasons and have other faults as well. Many allow unfiltered air to get around parts of the masks which don't hold tightly against the curves on the face of the wearer. Some of these masks may cause the face to perspire and to collect dust on the face around the edges of the masks. They also tend to cause fog to form on the eyeglasses of the wearer. My invention reduces the discomfort of wearing a mask, the air bypass or leakage, perspiration, and the fogging of eyeglasses which are caused by the wearing of other masks. My invention is relatively inexpensive to produce, is light in weight, and is held tightly in place without any strings or straps which go around the head or the ears.
My invention has significant benefits over other inventions in the field. Some inventions (U.S. Pat. No. 4,240,420 to Riaboy and U.S. Pat. No. 4,354,489 to Riaboy) use an adhesive strip which goes around the edge of the mask and holds it in place. To hold the mask in place, this strip adheres to the bridge of the nose, the upper lip, and the part of the face around the nose. Disadvantages of this mask are that heat, perspiration, and moist air from the lungs are trapped within the mask. This, along with the movement of the facial skin, tend to loosen the mask and let air in and out along the edges, and lessen its ability to stay on the face. In addition, the warm air discharged around the upper part of the nose will fog the eyeglasses of the wearer.
Another invention (U.S. Pat. No. 4,004,584 to Geaney) has a filter element held to the base of the nose with an adhesive strip around the perimeter of the element which adheres to the base of the nose. One of the disadvantages of this filter is that it has to be shaped accurately for each noes in order that the adhesive portion engages the outside areas of the base of the nose. Another disadvantage is that the air passing through the filter and the filter's weight pull the adhesive directly away from the skin: thus, the filter would fall off rather easily in active use. My invention eliminates these disadvantages.
Other air filtering masks which press against the face all around the nose (such as U.S. Pat. No. 3,695,265 to Brevik) allow air to escape and enter all around the edges of the masks because it is difficult to get their shape to conform exactly to the different facial contours of different people. The air entering around the edges isn't filtered, and the air escaping around the top of the masks will cause condensation on the eyeglasses of a wearer. In addition to these disadvantages, if the mask is held on with an adhesive strip around the perimeter of the mask (like the Riaboy, supra, inventions), the mask will loosen easily and be likely to fall off in active use. If the mask is held on by a spot of adhesive against the tip of the nose (like the Brevik, supra, invention) the force of the air passing out of the mask and the weight of the mask will pull the adhesive almost directly away from the nose and cause the mask to come off the face rather easily. My invention eliminates all these problems.
Breathing filters held against the base of the nose with strings and mechanical devices (such as disclosed in the French Patent No. 684,622 of Ogrisek and Piccard) have the disadvantages of being difficult to fit and to adjust the strings and other mechanical parts. In addition, the mechanical part would interfere with the eyeglasses of a wearer of eyeglasses, the device could get knocked off the nose easily, and the bearing points of the mechanical device would probably put uncomfortable pressure against the nose. My invention is comfortable, is not easily dislodged, is easy to apply, will fit easily and properly on almost any wearer, and needs no adjustment.